Every printed circuit board that leaves a factory faces the same enemies: moisture, dust, salt, fungus, vibration and temperature swings. A conformal coating — a thin polymeric film applied over the assembled board — is the cheapest insurance against all of them. But the most common question we get from Indian electronics and defence manufacturers isn't whether to coat; it's which chemistry to use. Acrylic or silicone? Here's a practical, standards-based way to decide.
What a conformal coating actually does
A conformal coating “conforms” to the contours of the board — components, traces and solder joints — leaving a 25–75 micron protective film. Unlike potting or encapsulation, it adds almost no weight and keeps the board serviceable. Done right, it prevents moisture ingress, surface corrosion, dendritic growth and high-voltage arcing, and it extends field life in harsh environments. Done wrong — or skipped — it's the difference between a board that survives a monsoon and one that fails in warranty.
The two workhorses: acrylic and silicone
Most industrial PCB protection comes down to two families.
Acrylic (AR). Fast-drying, easy to apply and inspect, and — critically — easy to rework: a technician can re-dissolve a patch with thinner, repair a joint, and re-coat. Acrylics give excellent dielectric strength and moisture resistance across a broad −70 °C to 120 °C range, which covers the vast majority of consumer, automotive and telecom electronics. Our Protektor® acrylic coatings dry to touch in about 30 minutes, deliver ~700 V breakdown at 26 microns, and are available with a UV tracer so inspectors can confirm complete coverage under UV light.
Silicone (SR). Where boards run hot, flex, or live in high-humidity or high-vibration environments, silicone earns its place. It tolerates a wider high-temperature band and offers superb moisture and thermal-cycling resistance, which is why it shows up in power electronics, LED drivers and under-hood automotive modules. The trade-off: silicone is harder to rework and needs more aggressive removal methods.
| Acrylic (Protektor 3100 / 3110 UV) | Silicone (Protektor SIL-26) | |
|---|---|---|
| Best for | General electronics, fast rework | High-temp, high-humidity, flexible boards |
| Rework | Easy (re-dissolvable) | Difficult |
| Temperature | −70 to 120 °C | Wider high-temp tolerance |
| Moisture resistance | High | Very high |
| Standard | IPC-CC-830C, MIL-I-46058C | IPC-CC-830B |
Let the standards decide, not the marketing
For anything mission-critical, the specification should drive the choice. IPC-CC-830C is the primary qualification standard for conformal coatings, covering materials, curing and electrical properties. For defence and aerospace assemblies, MIL-I-46058C remains the referenced benchmark. If your customer or end-application calls out either standard, your coating must actually conform to it — not merely “meet the spirit of it.” (Protektor acrylic coatings conform to IPC-CC-830C and MIL-I-46058C and are C-DOT approved and RoHS compliant; the silicone variant conforms to IPC-CC-830B.)
A simple decision rule:
- Rework matters / general electronics → acrylic.
- High heat, humidity or flex → silicone.
- Need to verify coverage in production → a UV-traceable acrylic.
- Defence/telecom spec calls out MIL/IPC → confirm the exact standard and match it.
Application notes that actually change field reliability
- Thickness discipline: aim for an even 25–75 µm; too thin under-protects, too thick can crack on thermal cycling.
- Cure and handle time: don't power or stack boards before the coating has set — trapped solvent causes defects.
- Coverage inspection: a UV tracer turns coverage from guesswork into a visible check — worth it on any assembly line.
- Rework planning: if your boards get repaired in the field, choose acrylic up front; retrofitting reworkability is impossible.
Why “made in India” matters here
Historically, spec-grade conformal coatings were imported at import-grade prices. That's changed. Coatings that conform to IPC-CC-830C and MIL-I-46058C are now manufactured in India — closing the cost and lead-time gap for Indian electronics, automotive and defence manufacturers without compromising on the standard. For a sector chasing self-reliance, local, certified chemistry is no longer a compromise; it's an advantage.
FAQ: acrylic vs silicone conformal coating
Which conformal coating is best for general electronics? For most consumer, automotive and telecom boards, an acrylic coating is the practical default — fast-drying, easy to inspect, and easy to rework.
When should I choose silicone instead of acrylic? Choose silicone when boards run hot, flex, or face high humidity or vibration — power electronics, LED drivers, under-hood modules — where its wider temperature tolerance and thermal-cycling resistance matter.
What standards should a PCB conformal coating meet? IPC-CC-830C is the primary qualification standard, and MIL-I-46058C is the referenced benchmark for defence and aerospace. Match whatever your application specifies.
What is the right conformal coating thickness? An even 25–75 microns. Too thin under-protects; too thick can crack under thermal cycling.
Can a conformal coating be reworked or removed? Acrylic coatings are re-dissolvable and easy to rework; silicone is harder to remove — so if field repairs are likely, choose acrylic up front.
Are Micron Aerosols conformal coatings made in India? Yes — the Protektor® acrylic range (IPC-CC-830C, MIL-I-46058C, C-DOT approved, RoHS) and the silicone variant (IPC-CC-830B) are manufactured in Sangamner, Maharashtra.
Related reading: What is Conformal Coating for PCBs and Conformal Coating Standards in PCB Manufacturing.
Micron Aerosols (a unit of Deepak Industries) has manufactured specialty chemicals and aerosols in Sangamner, Maharashtra since 1989 — including the Protektor® range of PCB conformal coatings, cleaners and thinners, plus anti-spatter, mould-release and maintenance sprays. ISO 9001 & 45001 certified. Learn more at micronaero.com.